Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare destructiveHint=true, readOnlyHint=false, and idempotentHint=false, so the safety profile is carried by structured data. The description adds nothing beyond that: it does not say what disabling does to already-received or queued mail, whether the change is reversible, or what permissions are required — the key questions for a destructive toggle. Note that the boolean setter semantics implied by the schema suggest idempotency, which sits awkwardly against idempotentHint=false, but this tension originates in the annotations rather than contradicting anything the description claims.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single eight-word sentence with the action and scope front-loaded and zero filler. Nothing is redundant or buried.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The schema is complete and annotations cover the safety profile, so the mechanical inputs are fully specified. However, for a destructive state change with no output schema, the description leaves the agent without consequences (what disabling forfeits), prerequisite ordering, or result behavior — meaningful gaps for this tool type.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% and both parameters ('enabled' as true/false for email, 'subdomain_id') are documented in the schema itself. The description adds no syntax, format, or edge-case detail beyond stating that email receiving is toggled, so the baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb pair (enable/disable) and the resource (email receiving for a subdomain), which is more precise than the title's 'email inbox'. It separates this from sibling toggles like toggle_subdomain and toggle_wildcard by naming the email-receiving scope, though it never explicitly names those siblings.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no guidance on when to use this versus toggle_subdomain, toggle_capture, or toggle_wildcard, and no mention of prerequisites such as the subdomain needing to be registered first. The agent must infer all usage conditions from the name alone.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.